• Journal of Scientific & Technological Knowledge Infrastructure
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• s.7
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• pp.141-148
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• 2001

This paper describes a mechanisms for IPv6 multihomming with loadsharing broker, focusing on the interdomain scalability and load sharing with redundancy on IPv6 networks. Unlike currently-practiced IPv4 multihoming, this model does not impact the worldwide routing table size, also it provides inbound load sharing at site level based on router renumbering, and multiple-prefix assigning techniques of IPv6. The proposed model has four modules such as building interfaces MIB module, priority list maintaining module, load detection module, and RRP configuration module.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.143-157
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• 2008

Ubiquitous Web Services is able to be specified future Web Services technology for connecting with various application services in any device and network environments. The devices, in ubiquitous environment, have dynamic characteristic such as location and statuse. So, we must support methods of dynamic service discovery in ad-hoc network. There are many related works at transaction, security, QoS, semantic and Web Services composition with various fields. Recently, the studies are interested in the Ubiquitous by development of computing and network technology. However, they are an early stage. For this reason, in this paper, we propose a WSUN(Web Services on Universal Networks) for Ubiquitous Web Services. It is a SOA based framework. And this paper extracts necessity of WSUN environment from scenario. The framework is composed of US Broker(Universal Service Broker). It is designed for satisfying the conditions and supports dynamic service discovery using a US Registry (Universal Service Registry). Consequently. clients are able to discover and use Universal Service by protocol stack of the US Broker for Web Services. And it is a strong point which supports interoperability between heterogeneous networks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.102-105
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• 2010

Traditional Pub/Sub(Publish/Subscribe) Systems search all subscriptions that match an incoming event by broker(i.e. it is not considering the accuracy of matching between an incoming event and subscriptions and only consider that an event either matches a subscription or not). However, subscriptions that match an event may have priority, therefore, we need priority Pub/Sub system. In this paper, we define what the accuracy means in order to prioritize among subscriptions and propose the Priority Retrieval Technique based on accuracy that able to search subscriptions. The Priority Retrieval Technique is based on IS-Lists. We can search the results ordered by accuracy.

• Korean Journal of Computational Design and Engineering
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• v.9 no.4
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• pp.361-372
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• 2004

Collaborative and distributed engineering web services are emerging as a viable alternative to the traditional design and engineering process automation. Existing approaches have limitations in supporting long-running engineering transactions, automatic engineering process orchestration and choreography, synchronous and asynchronous conversation, and geometric abstraction for transmission and sharing. In this paper, we present a process-centric engineering web service methodology to overcome these limitations by utilizing BPEL-based (Business Process Execution Language) process templates and coordination broker-based conversation support. This paper discusses the synchronization of engineering web services which can be either peer-centric or process-centric to support long-running engineering transactions and conversation. The process orchestration and choreography broker works as a service dispatching and aggregation mediator for executing process templates, which enables the individual activity or the engineering process to dynamically select and invoke one of the alternative web services through the run-time process brokering. Further, the paper presents how to support collaboration over the running process using conversation policy.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.78-84
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• 2002

In this thesis a shipping broker agent system, which can be executed by a CORBA-based environment using the distributed object technique, CORBA is designed and implemented Nowadays, while the EC system is extensive on the web, legacy host systems have limitations and its capacity-upgrade os required. In order to solve these problems the method that distributes programs into several computer systems can reduce their loads, set low system capacity and minimize network bottleneck. In this thesis using Agent Communication Language(ACL), we propose an agent based prototype and implement an intelligent agent prototype for ships search using CORBA, which can exchange and shiare data between different systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.116-118
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• 2018

This paper introduces oneM2M global IoT standard middleware platform based smart city service data model support and FIWARENGSI interworking for Orion Broker. Also, service data models implementation using flexContainer resource types and FIWARENGSI interworking using the Interworking Framework (TS-0033) from oneM2M Release 3 are also illustrated. In this system, data model element level access (e.g. for subscription/notification feature) is enabled, which is enhancement compared to contentInstance resource type before, and service agnostic FIWARE NGSI interworking is provided over the Interworking Framework for smart city platform data interworking.

• KNOM Review
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• v.22 no.1
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• pp.30-41
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• 2019

MQTT protocol is one of open Publish / Subscribe systems for IoT information transmission. In this paper, we are proposing an algorithm to assign a subscriber, which dynamically participate in MQTT clustering system, to an appropriate broker. In MQTT systems with a centralized broker, there are losses of connectivity and messages between subscribers and brokers. In this paper, we addressed this issue for developing scalable open IoT systems and consider clustering MQTT brokers on the SDN infrastructure. In particular, this paper focuses on the problem of allocating subscribers to brokers in accordance with sharing brokers' topics to reduce brokers' load and communication cost in SDN based MQTT cluster. The Experimental results show that the proposed algorithm will reduce the load and the cost as compared to existing methods.

• Journal of KIISE:Information Networking
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• v.30 no.2
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• pp.199-206
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• 2003

one of the representative micropayment protocols. The original PayWord system is designed for a user who generates paywords by performing hash chain operation for payment to an only designated vendor. In other words, a user has to create new hash chain values in order to establish commercial transactions with different vendors on the Internet. Therefore, we suggest an efficient scheme that is able to deal with business to different vendors by using only one hash chain operation to supplement this drawback. In this proposed system, a broker creates a new series of hash chain values along with a certificate for the user's certificate request. This certificate is signed by a broker to give authority enabling a user to generate hash chain values. hew hash chain values generated by a broker provide means to a user to do business with multiple vendors.

• KIISE Transactions on Computing Practices
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• v.20 no.12
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• pp.688-693
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• 2014

With the advent of ubiquitous environments, the smart phone has come into wide use and the demand for various content increases. Thus, in order to efficiently utilize limited resources cognitive radio technology is regarded as a possible solution. Besides spectrum sensing or access schemes, the provision of VoIP traffic service for secondary users with limited spectrum resources is a very important issue. In this paper, a resource allocation and control system for VoIP QoS provision in cognitive radio networks is proposed. Firstly, as the system model, the time structure of the network is addressed and, according to the structure, a bandwidth broker is proposed. In addition, based on available bandwidth estimated by the bandwidth broker, a connection admission control for secondary users is developed. It is demonstrated that the provision of VoIP QoS is greatly affected by channel utilization, the number of channels, and the length of timeslot.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4B
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• pp.444-454
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• 2004

To support diverse transmission requirements of multimedia applications, Quality of Service (QoS) should be provided in the Internet, where only the best-effort service is available. In this paper, we describe our recent effort on the implementation and verification of an extendable and flexible QoS allocation and resource management system based on the bandwidth broker model for realizing the IETF differentiated service (DiffServ). Focusing on the bandwidth issue over single administrative domain, the implemented system provides real-time resource reservation and allocation, delayed call admission control, simple QoS negotiation between sewer and users, and simple resource monitoring. The implemented system is verified by evaluating the performance of a resource-intensive application over the real-world testbed network.